1. Technical Field
The technical field relates to a printing apparatus and more particularly relates to a three-dimensional printing apparatus and a method of compensating a coordinate offset between nozzles thereof.
2. Description of Related Art
With the progress in computer-aided manufacturing (CAM), manufacturers have developed the technology of three-dimensional (3-D) printing for rapidly embodying an original design concept. In fact, the 3-D printing technology is a collective term referring to a series of rapid prototyping (RP) techniques, and the basic principle is laminate manufacture, wherein a rapid prototyping machine is used to form cross-sectional shapes of a workpiece in the X-Y plane through scanning, shift intermittently at a layer thickness in the Z coordinates, and ultimately form 3-D objects. The 3-D printing technology is applicable regardless of the geometric shapes and the RP technology produces excellent outputs in particular for complex parts, which saves efforts and processing time significantly. The 3-D printing technology is capable of presenting an object of a digital 3-D model designed by means of computer-aided design (CAD) software in less time for the user to touch and actually feel the geometry of the model, or even to test the assemblability of the parts and possible functions.
Currently, most three-dimensional printing apparatuses, which utilize the rapid prototyping (RP) technique to form a three-dimensional object, use a material feeding mechanism to supply a hot melt forming material to the nozzle and then heat and melt the material by means of a material heating structure and the nozzle, so as to apply the hot melt forming material layer by layer on the platform to form the three-dimensional object. In order to improve the practicality of the three-dimensional printing apparatus and the diversity of the three-dimensional objects, manufacturers in this field start developing a printing head module with multiple nozzles, and the nozzles can alternately apply different forming materials or forming materials of different colors onto the platform. However, for the printing head module with multiple nozzles, the nozzles may be displaced from the predetermined positions due to various factors such as assembly errors of the factory or usage. As a result, the relative positions of the nozzles may be offset. The offset error of the nozzles may cause improper bonding, such as displacement and overlap, of the joint between different forming materials. For this reason, the three-dimensional object may not be printed as expected, and the printing quality and printing yield of the three-dimensional printing apparatus are reduced.